Trench duct assembly with adjustable lid supporting members



April 1, 1969 H. J; HOSEASON ETAL 3,435,568

TRENCH DUCT ASSEMBLY WITH ADJUSTABLE LID SUPPORTING MEMBERS Sht of 2 'Filed March 31, v 1967 0 0 7 3 o 5 o 2. 61' On I n a? 4 H 3 A. 0.1 3 Q 3 51L 2 I 3 F w m m w 4.\ m6 W 7 3 M 9 2 (.r 2 4 m 4 G 3/N I 7 9 F Y 3 W 5 T 2 m :1 J i 3 :5? B

1 V ENTORS HARRY J. HOSEASON WALTER R. PACKMAN B I U ATTORNEYS v April 1, 1969 H. J. HOSEASON ETAL 3,435,568

TRENCH DUCT ASSEMBLY WITH ADJUSTABLE LID SUPPORTING MEMBERS Filed March 51, 1967 Sheet 2 l "E.\"TOR S HARRY J. HOSEASON WALTER R. PACKMAN ATTORNEYS United States Patent US. Cl. 52-221 9 Claims ABSTRACT OF THE DISCLOSURE An underfloor trench duct is composed of end-abutting sections, each comprising a base, a pair of upstanding side walls, a lid assembly covering the duct and a pair of longitudinally extending lid supporting members supported on the side walls, the lid supporting members being adjustable as to height. Each lid supporting member has an inverted U-shaped vertical channel portion engaging over the side wall, an inwardly directed horizontal flange integral with and on top of the vertical channel portion and projecting into the duct, an upwardly extending vertical flange located on the opposite side of the lid supporting member to the inwardly extending flange, and a dovetail portion outside the duct. A plurality of dovetail clamps engage over the dovetail portion, and the heights of the lid supporting members are adjustable by means of jack screws carried by the dovetail clamps.

BACKGROUND OF THE INVENTION Field of invention This invention relates to underfloor trench ducts for wiring distribution systems.

Underfloor trench ducts are commonly used for wiring distribution systems in hospitals, office buildings, and other buildings in which a large number of electrical outlets are required. Trench ducts are commonly embedded in a poured concrete floor, and removable closure-s are provided so that electricians may have access to the internal wires and cables. It has been proposed to provide an underfloor trench duct with a removable lid assembly, which would normally be covered by a floor covering such as tiles, in order that the interior of the duct might be more readily accessible. However, since the duct is placed in position before the concrete is poured it is important that the duct should not move during pouring of the concrete, because any such movement would lead to irregularities in the level of the finished floor surface. It is therefore desirable that the lid assembly should be adjustable.

Description of prior art US. Patent No. 2,081,197 discloses a simple box-like floor conduit which uses outside levelling screws. There are no inside obstructions in the conduit shown by the patent. US. Patent No. 2,176,439 relates to pneumatic dispatch system which has no inside connectors or other obstructing elements. US. Patent No. 2,812,654 utilizes outside levelling screws and has no inner obstructing elements. The duct shown in this patent does not appear to have a removable top nor does it utilize aligning elements at the duct joints. US. Patent No. 3,074,208 discloses a floor duct with outside levelling screws and a readily removable lid, but the construction does not use a clip-on lid nor aligning elements at the joints of the duct sections.

US. Patents Nos. 3,084,480 and 3,237,356 are concerned with an electrical trench with levelling screws located partially inside the duct section. US. Patent No. 3,101,097 discloses a special type of closure plate for an underfloor duct, in which levelling screws are located under the duct cover but not inside the duct itself and there is no obstruction in the duct passageway. Furthermore, the patent does not disclose aligning elements for the duct nor releasable clip elements for the cover plates. US. Patent No. 3,166,663 discloses an adjustable cover plate on a trench duct utilizing inside adjusting screws.

None of the patents referred to above shows a trench duct assembly of the kind to which the invention relates, and having exterior levelling screws.

It is one object of the present invention to provide a trench duct assembly of robust construction in which the height of the lid assembly can be readily adjusted.

''It is another object of the invention to provide a trench duct assembly including adjustable lid supporting means which may be adjusted to the correct height prior to pouring of the concrete and thereafter embedded in the concrete.

None of the patents mentioned above shows a trench duct assembly of thekind to which the present invention relates, and having exterior levelling screws.

SUMMARY OF THE INVENTION The invention provides in a trench duct assembly for a wiring distribution system comprising a duct with a base, a pair of upstanding side walls integrally attached to the base, a lid assembly covering the duct and a pair of longitudinally extending lid supporting members adjustable as to height from the base and supported on the side walls, the improvement comprising an integral lid supporting member on each side of the duct having an inverted U- shapcd vertical channel portion on the lower end thereof engageable over said upstanding side wall, an inwardly extending horizontal flange on top of and integral with said vertical channel portion and projecting into said duct, an upwardly extending vertical flange on top of and integral with said channel portion and located on the opposite side of the lid supporting member to said inwardly extending flange, the vertical flange being located outside said lid assembly with its top surface at substantially the same level as the top surface of the lid assembly and a dovetail portion outside the duct and integral with and extending outwardly from the outside of the channel portion on the lid supporting member, a plurality of dovetail clamps engageable over said dovetail portion, a jack screw located in each said dovetail clamp for adjusting the height of said lid supporting member and a plurality of lid holding members engageable with said lid assembly and with said inwardly extending flange.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described b way of example, with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view, partly broken away, of a portion of a trench duct assembly according to the invention;

FIGURE 2 is a cross-sectional view of a detail of the assembly, the figure showing the lid in a temporary position.

FIGURE 3 is a cross-sectional view of a detail of the assembly, the figure showing the lid in the normal position;

FIGURE 4 is a section on line 4-4 of FIGURE 1;

FIGURE 5 illustrates an alternative form of lid holding member, and

FIGURE 6 illustrates a detail of another portion of the assembly of FIGURE 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGURE 1, an underfloor trench duct 1 for a wiring distribution system is embedded in a concrete floor 2, the upper edges of the duct being flush with the surface of the concrete, and the whole floor surface being covered with tiles 3. The trench duct is of rectangular cross-section and comprises a base 4, a pair of upstanding side wall 5 integrally attached thereto, a lid assembly 6 covering the duct 1, and pair of longitudinally extending adjustable lid supporting members 7 supported on the side walls 5. As shown also in FIGURES 2 and 3, the side walls are angle members each having a base flange 8 welded to the base 4 adjacent to the edge of the latter, and an upstanding flange which constitutes the side wall proper. The side walls 5 are parallel to one another. The lid assembly 6 comprises a series of plates arranged in edge abutting relationship and each extending across the whole width of the duct between the lid supporting members 7.

Each lid supporting member 7 consists of an aluminum extrusion formed with an inverted U-shaped vertical channel portion 9 on its lower end which engages over an upstanding side wall 5, an inwardly extending horizontal flange 10 on top of and integral with the channel portion 9, the flange 10 projecting into the duct 1, and an upwardl extending vertical flange 11 on the top of and integral with the channel portion 9, the flange 11 being located on the opposite side of the member 7 to the flange 10. The vertical flange 11 is located outside the lid assembly 6 with its top surface at substantially the same level as the top surface of the lid assembly.

Integral with the channel portion 9 outside the duct 1 is a dovetail portion 12. A plurality of dovetail clamps 13, 13a and 13b (see FIG. 6) engage over the dovetail portion, the clamps being longitudinally adjustable thereon. Each dovetail clamp 13 comprises a block having a channel of dovetail cross-section in one side face, a vertical threaded hole through which a jack screw 14 extends, and a horizontal threaded hole to receive a clamping screw 15 for clamping the dovetail clamp 13 to the lid supporting member 7. Each dovetail clamp 13a also comprises a block having a channel of dovetail cross-section in one side face, a horizontal threaded hole which receives a clamping screw 15a, and a vertical threaded hole which receives a vertical clamping screw 17. The lower end of the clamping screw 17 extends through a slot in the upper limb of a U-shaped stirrup 19, the lower end of the clamping screw 17 having a head 18 which engages the underside of the limb. The stirrup members 19 engage over the base flanges 8 of the trench duct sections, along which they can be moved as necessary.

The trench duct is made up of sections, each about five feet long, abutting end to end, and the lid assembly 6 preferably consists of two lid plates per section. Dovetail clamps such as 13b are provided at the joints between trench sections to ensure their horizontal alignment. Each clamp 13b comprises a block which extends longitudinally across the joints so as to engage both sections. Through the block extend a pair of clamping screws 15b, and a jack screw 16, the jack screw 16 having a head at its lower end which bears on the abutting flanges 8. It will be observed that the clamps 13b serve to maintain the alignment of the dovetail flanges 12 to which they are clamped.

A partition 20, forming a barrier between sections of the duct, extends along the duct. The partition 20 comprises an angle member having a base flange 21 welded to the base 4 of the duct and an upstanding flange 22 formed with short vertical slots at intervals. A second angle member has a horizontal upper flange 23 and a vertical flange 24 which overlaps the flange 22, the angle members being bolted together by bolts 25. This construction enables the partition to be preset at the correct height.

Dust stops are provided at abutting edges of adjacent lid plates. One such dust stop is illustrated in FIGURE 4. An angle member 26 extends along the transverse edge of each lid plate 27, the angle member 26 having a horizontal flange 28 which lies against the underside of a plate 27, and an upstanding flange 29, which projects beyond the upper surface of the plate 27 by an amount equal to the thickness of the flange 28, the said amount being equal to the thickness of a tile 3. Welded to the underside of one of the plates 27 is a stepped member 30 having a stepped or oflset portion 31 which is spaced from the underside of the flanges 28, the space between them being filled with a neoprene-cork layer 32. The vertical flanges 29, which are optional features of the construction, serve as tile stops for locating the tiles 3.

An aluminum extruded angle member 33 is riveted along each longitudinal edge of a lid plate. The member 33 has a horizontal flange 34 which normally lies against the underside of the lid plate, and a vertical flange 35 which projects above the top surface of the lid plate by an amount equal to the thickness of the flange 34. The said amount is equal to the thickness of a tile 3. As shown in FIGURE 3, a longitudinal strip 36 of cushioning material, such as neoprene-cork, is clamped between each flange 34 and the flange 10 of the lid supporting member 7, clamping being effected by lid holding members, which will now be described.

A plurality of screw seats each comprising a block 37, of which one is shown in FIGURE 3, are mounted at the inner edge of the horizontal flange 10 of the lid supporting member, the mounting being effected by a cooperating bead and groove. The block 37 has a vertical threaded hole 38 adapted to receive the lower end of a clamping screw 39, the screw 39 being located on a seating member 40 on the upper surface of a lid plate and extending through a hole 41 in the latter. The blocks 37 may be longitudinally adjusted, in order to align the holes 38 with the clamping screws 39, and clamped in position by screws 42.

An alternative lid holding arrangement is illustrated in FIGURE 5. In this alternative arrangement the holding member comprises a captive rotatable pin 43 located in a hole in the lid plate. The pin 43 has a slotted head 44 and is retained by a split washer 45 located in an annular groove 46. At the lower end of the pin 43 is a radially extending cam member 47 carrying a cam surface 48 which is adapted to engage the underside of the horizontal flange 10. In FIGURE 5 the full lines show the lid holding member in the clamping position and the broken lines show the lid holding member in the release position.

According to the invention either form of holding member may be used; the first is preferred because it is less vulnerable to accidental displacement or tampering.

In laying the trench duct assembly according to the invention the sections of duct are placed end to end in the trench and are levelled by appropriate adjustment of the jack screws 14 and by setting the clamps 13b. The clamps 13a are set to the required positions. The lid assembly 6 is next placed over the duct, the lid plates being upside down as illustrated in FIGURE 2. In this operation the lid assembly is clamped down by temporary screws 49. The jack screws 14 and 16 are next adjusted to bring the lid supporting members exactly to the required height, the screws 17 are tightened, and the concrete is poured. It will be noted that the upper surfaces of the horizontal flanges 34, when the lid assembly is in this position, are flush with the surface of the concrete floor, whereas if the lid assembly is reversed the projecting edges of the flanges 35 are flush with the tiled surface. After the concrete has set no further height adjustment of the lid supporting members is possible. The temporary screws 49 are next removed and the lid assembl 6 is reversed and clamped down by the lid holding members, which are of the form shown in FIGURE 3 or FIGURE 5. When the lid holding assembly is reversed its upper surface is at exactly the correct level to receive the tiles 3, which provide a uniformly level floor surface,

In order to gain access to the interior of the duct 1 after it is assembled, screws 50, which engage threaded holes in the lid plates, are removed to expose circular holes 51 in the tiles 3. A lid-lifting tool 52 having a screw-threaded end 53 may now be inserted into a hole 51 and brought into engagement with a threaded hole in the lid for lifting the latter. When the lid, or any section of it, has been removed it may readily be replaced and again secured to the lid supporting members by the screws 50. The modified arrangement of FIGURE 5 enables the lid to be removed or replaced even more simply, since the heads 44 of the pins 43 are accessible, lying flush with the upper surface of the tiled floor, and can simply be turned b means of a screwdriver.

What we claim as our invention is:

1. In a trench duct assembly for a wiring distribution system comprising a duct with a base, a pair of upstanding side walls integrally attached thereto, a lid assembly covering said duct and a pair of longitudinally extending lid supporting members adjustable as to height from said base and supported on said side walls, the improvement comprising an integral lid supporting member on each side of the duct having an inverted U-shaped vertical channel portion on the lower end thereof engageable over said upstanding side wall, an inwardly extending horizontal flange on top of an integral with said vertical channel portion and projecting into said duct, an upwardly extending vertical flange on top of and integral with said channel portion and located on the opposite side of the lid supporting member to said inwardly extending flange, the vertical flange being located outside and said lid assembly with its top surface at substantially the same level as the top surface of the lid assembly and a horizontally extending dovetail portion outside the duct and integral with and extending outwardly from the outside of the channel portion on the lid supporting member, a plurality of dovetail clamps engageable over said dovetail portion, a jack screw located in each said dovetail clamp for adjusting the height of said lid supporting member and a plurality of lid holding members engageable with said lid assembly and with said inwardly extending flange.

2. A trench d-uct assembly according to claim 1, in which a plurality of screw seats are mounted at the inner edge of the horizontal flange, and in which each lid holding member comprises a clamping screw extending through the lid assembly and engaging in a vertical threaded hole in the screw seat.

3. A trench duct according to claim 2, in which the screw seat is longitudinally adjustable on the horizontal flange for aligning the vertical threaded hole with the clamping screw.

4. A trench duct assembly according to claim 1, in which each lid holding member comprises a captive, rotatable pin extending vertically through the lid assembly, and carrying at its lower end a cam member adapted to engage the underside of the horizontal flange.

5. A trench duct assembly according to claim 1, in which a longitudinally extending strip of cushioning material is located between the underside of the lid assembly and each horizontal flange, the strip constituting a gasket and being clamped between said underside and said horizontal flange.

6. A trench duct assembly according to claim 1, in which a longitudinally extending angle member is secured along each longitudinal edge of the lid assembly, each angle member comprising a first spacer portion projecting above the upper surface of the lid assembly by a predetermined amount corresponding to a title thickness, .and a second spacer portion projecting below the lower surface of the lid assembly by the same amount, whereby height adjustment of the lid assembly may be carried out when the lid assembly is upside down, no further height adjustment being necessary when the lid assembly is reversed.

7. In a trench duct assembly according to claim 1, the duct consisting of sections abutting end to end, the improvement comprising a dovetail clamp on each side of the duct, the clamp being engageable over a respective dovetail portion of a lid supporting member and engaging end-abutting dovetail portions of two adjacent duct sections, a jack screw located in each dovetail clamp for adjusting the height of the lid supporting member, the jack screw engaging the duct sections, and a pair of clamping screws for clamping each dovetail clamp to the lid supporting members of the duct sections.

8. A trench duct assembly according to claim 1, in which the lid assembly comprises a plurality of plates mounted in edge abutting relation to one another, and in which dust stops are provided between pairs of abutting edges of the plates, each dust stop comprising a metal strip formed with a longitudinal step therein, the metal strip being welded to the underside of one plate and having a longitudinally extending stepped portion which extends under .an adjacent plate and is spaced therefrom, a gasket being located between the stepped portion of the strip and the underside of said adjacent plate.

9. In a trench duct assembly for a wiring distribution system comprising a duct with a base, a pair of upstanding side walls integrally attached thereto, a lid assembly covering said duct and a pair of longitudinally extending lid supporting members adjustable as to height from said base and supported on said side walls, the improvement comprising an integral lid supporting member on each side of the duct having an inverted U-shaped vertical channel portion on the lower end thereof engageable over said upstanding side wall, an inwardly extending horizontal flange on top of and integral with said vertical channel portion and projecting into said duct, an upwardly extending vertical flange on top of and integral with said channel portion and located on the opposite side of the lid supporting member to said inwardly extending flange, the vertical flange being located outside said lid assembly with its top surface at substantially the same level as the top surface of the lid assembly, and a dovetail portion outside the duct and integral with and extending outwardly from the outside of the channel portion of the lid supporting member, a plurality of dovetail clamps engageable over said dovetail portion, a jack screw located in each said dovetail clamp for adjusting the height of said lid supporting member, a plurality of lid holding members engageable with said lid assembly and with said inwardly extending flange, each lid holding member comprising a clamping screw, and a plurality of longitudinally adjustable screw seats on the horizontal flange for aligning the vertical threaded hole with the clamping screw.

References Cited UNITED STATES PATENTS 740,663 10/ 1903 Krantz 2203.7 1,782,779 11/1930 Pullman 52221 2,054,568 9/ 1936 Beach 254-133 2,601,213 6/ 1952 Poupitch 2.87-189.36 2,883,228 4/1959 Roberts 2203.8 X 3,074,208 l/ 1063 Seidel 52-221 3,204,378 9/ 1965 Stuesel et a1. 52-221 3,262,238 7/ 1966 Fork 52122 X FOREIGN PATENTS 476,625 12/ 1937 Great Britain.

133,029 7/ 1929 Switzerland.

ALFRED C. PERHAM, Primary Examiner.

US. Cl. X.R. 

